1. Field of the Invention:
The art of coating plant seeds is highly developed and is known to have many and sundry applications in the field of agriculture.
Certain plant seeds perform better in soils of varying pH levels, for example, alfalfa seed performs best in neutral to alkaline soils. Alfalfa seeds, for example, have a naturally occuring waxy layer on their surfaces against which some water soluble or water dispersible film-forming polymers will tend to form a snug envelope. However when seed is processed at the seed manufacturing point coatings which may be applied during seed processing are often broken in shipment to the field for implantation. As a result it has been a practice in the case of alfalfa to coat seeds with such treatments as lime in very small batches for use near to the agricultural regions.
By chemically treating seeds with various forms of chemicals to protect the seed and alter the immediate region around the seed against unfavorable pH soil conditions extensive working of the soil in the field is avoided. As illustrated in U.S. Pat. No. 3,808,740 the alternative to coating individual seeds with an alkaline substance is to apply 1-5 tons of an agent such as limestone per acre to the soil well in advance of planting. Manifestly applying the chemical agent directly to the soil is wasteful insofar as the seed soil interface is the only pertinent area to the germination of the seed.
According to the device of the instant invention a portable self contained apparatus is disclosed which allows for seed to be treated immediately in the field, particularly the device according to the instant invention may be mounted on the back of a field vehicle such as a pick-up truck to apply the chemical treatment to the seed in a particularly efficient manner without the danger of damage to the coating during handling between a distant seed treating facility and the point of use.
2. Description of the Prior Art
Various prior art devices have been proposed for applying various forms of perservative, both liquid and granular, to seed.
It should be remembered that plant seeds are fertilized ova already somewhat developed morphologically as embryonic plants, usually having more or less of a food supply and a protective seed coat (both angiosperms and gymnosperms). The seed coat provides protection for the food supply (e.g., endo sperm and cotyledons) and zygote, and this coat often functions to retard germination until environmental conditions are hospitable.
However, there has not existed in the prior art a device which is particularly suited for portable use that allows particularly efficient coating of a thin curtain of seed through a horizontal impingement of opposed treatment chemical sprays. The device according to the instant invention is usable with any number of a type of well-known chemical treatment agents, and the particularly utility of the device resides in its portability combined with its efficient manner of spraying a thin curtain of seed through a self-contained device which is more particularly taught hereinafter.
The following patents illustrate sundry types of apparatus and chemicals which are known in the prior art:
Australia 22,575 Netherlands 20,074 Netherlands 40,185 PORTER 3,808,740 KNAPP 3,775,034 BRATSCHITSCH 3,734,777 KIRK 3,703,404 SCHREIBER 3,698,133 NAU 3,666,523 HEDEN 3,605,688 SCHREIBER 3,545,129 COOK 3,477,842 DICKINSON 3,460,492 WATANABE 3,454,404 GISIGER 3,198,655 WURSTER 3,196,827 RECKON 3,173,794 WILSON 3,158,462 CORDELL 3,155,542 GATZKE 3,130,694 HOPKINS 2,973,740 GUSTAFSON 2,823,904 GUYER 2,644,676 MAHONEY 2,594,469 BURGESSER 2,579,733 COOPER 2,097,914 LAMB 2,071,846 BRANDUS 1,970,163 CALKINS 1,573,142
However in all of these prior art devices the teachings are for a specific chemical treatment with a type of tumbling coating operation which is less advantageous than the portable liquid pressure spray seed treater as is taught herein.
Specifically, patents to Porter, Kirk, Brink, Watanabe, Wilson, Brandus and the two patents to Schreiber disclose specific seed treatment chemical agents with no particularization to the apparatus as taught herein. For example, Kirk at column 4 tumbles a mixture of seed under a spray for a period of four hours together with a mixture of separate porous particles.
The two Netherlands patents and the Australian patent illustrate seed coating devices involving another tumbling operation and in the case of the later Netherlands patent a further mechanical treatment of seed through contact between rollers.
The patents to Knapp, Brink, and Schreiber, '129 illustrate prior art devices for pelletizing and encapsulating seed within a type of organic binder material. Schreiber further teaches an apparatus which requires an air suspension of seed through a series of manufacturing steps.
The patent to Bratschitsch illustrates a spray device where grain is conveyed and tumbled mechanically by an auger past a nozzle assembly. The patent to Cordell is a seed treating device which requires that the seed be mechanically agitated by an auger during the coating process. Similarly the seed treating devices in the patents to Calkins, Burgesser, and Guyer further illustrate mechanical agitating devices which are unsuitable for certain seeds, particularly soybeans. Such mechanical agitation would bruise delicate seed, such as soybean and unlike the thin curtain liquid seed treater as taught by the instant invention they would be unsuitable for treatment of delicate seed with very small quantities of chemicals.
The problem of bruising the seed is addressed in the patent to Garzke which employs a mechanical agitation of a seed and water slurry to minimize bruising. However, unlike the present invention a water slurry is necessary and is normally unavailable for on-site field planting operations. Various other apparatus for treating particulate matter are known where the particulate material is subject to a spring operation. The patent to Nau illustrates such a form of a hopper spray for creating granules of fertilizer previous to a conveying, mixing and tumbling operation for agglomerating the particular fertilizer granules. Fertilizer materials are not analogous to delicate seed, and Nau's device does not recognize the problems attendant to delicate seed treatment. The patent to Cook is another fertilizer treating device which employs spray nozzles and insofar as the problems of delicate seed treatment are not recognized is similarly not analogous. Similarly the patents to Hopkins, Mahoney, Cooper and Lamb are concerned with various apparatus and methods for spraying freely falling particulate matter other than seeds, and do not teach or resolve the problems of treating delicate seeds with small amounts of chemical treating agents. Furthermore there is no teaching in these non-analogous devices for controlling the width of a thin curtain of seed in conjunction with the pressure supplied to a subsequent chemical spray treatment assembly.
Process and apparatus for treating harvested grain in Reckon include a grinding operation and, of course, is not concerned with damage to a delicate seed, which problem being addressed and solved by the apparatus according to the instant invention.
Representative of seed treating prior art is Gustafson's use of a paddle or spreader assembly for agitation, and insofar as any mechanical agitating device would bruise delicate seed, such as soybeans, his teachings are not addressed to the problems of the instant application.
The patent to Dickinson teaches a process for violently agitating seeds in order to coat them with a magnetic material, and his continuous process employs a reverse air-flow to turbulently mix seed which is introduced within a slurry of chemicals. The patent to Wurster similarly is a violent agitation device unlike the thin curtain treatment device of the instant invention.
Finally other non-portable seed treating apparatus known are exemplified by the patents to Heden and Gisiger where a seed is supplied from a hopper for a type of contact with a chemical mix. Heden uses a spinning plate to centrifically accelerate seed outward and Gisiger employs an atomizing spray; however, the seeds themselves are first subject to a mechanical mixing agitation through paddles and a subsequent agitation through paddles. Such agitation and mechanical abrasion is inapplicable to delicate seed coats, such as has been discussed with respect to soybeans.